Automatic honing stone expansion device

ABSTRACT

A honing stone expansion device for use in a honing machine in which a plurality of hone holders are radially outwardly disposed around a main body fixedly mounted on a rotatable shaft. Each of the hone holders to be expanded synchronously by hydraulic pressure is further provided with a honing stone extrusion device and locking means for the honing stone also operated by hydraulic pressure for easy adjustment of the height of the honing stones to be projected from the hone holders and for securely locking the same to the holders.

United States Patent [1 1 Yoshino AUTOMATIC I-IONING STONE EXPANSIONDEVICE [75] Inventor: Tsutomu Yoshino, Hiroshima, Japan [73] Assignee:Toyo Kogyo Co., Ltd., Hiroshima,

Japan 22 Filed: Aug. 30, 1974 21 Appl. No.: 502,239

[30] Foreign Application Priority Data Sept. 4, 1973 Japan 48-99622 [52]U.S. Cl. 51/349; 51/DIG. 32 [51] Int. Cl. B24B 33/06 [58] Field ofSearch 51/1659, 165.93, 349, 51/352, DIG. 32

[56] References Cited UNITED STATES PATENTS 2,631,414 3/1953 Muehling51/349 X 3,774,346 11/1973 Hoglund 51/DIG. 32

[ Oct. 21, 1975 3,851,422 12/1974 Dojyo 51/DIG. 32 FOREIGN PATENTS ORAPPLICATIONS 652,022 10/1937 Germany 51/349 1,045,841 12/1958 GermanySl/DIG. 32

, Primary Examiner-Al Lawrence Smith Assistant ExaminerNicholas P.Godici Attorney, Agent, or FirmWenderoth, Lind & Ponack [5 7] ABSTRACT Ahoning stone expansion device for use in a honing machine in which aplurality of bone holders are radially outwardly disposed around a mainbody fixedly mounted on a rotatable shaft. Each of the hone holders tobe expanded synchronously by hydraulic pressure is further provided witha honing stone extrusion device and locking means for the honing stonealso operated by hydraulic pressure for easy adjustment of the height ofthe honing stones to be projected from the hone holders and for securelylocking the same to the holders.

7 Claims, 9 Drawing Figures US. Patent 0321,1975 $1163 10 3,913,283

U.S. Patent Oct. 21, 1975 Sheet 2 of3 3,913,283

F/GJ

FIG. 4

FIG. 9

US. Patent Oct. 21, 1975 Sheet30f3 3,913,283

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AUTOMATIC HONING STONE EXPANSION DEVICE The present invention relates toa honing machine to be used for polishing a trochoidal multilobed innersurface of a workpiece and more particularly, to an automatic honingstone expansion device for use therein.

conventionally, in the honing stone expansion device of the abovedescribed kind, a plurality of hone holders for honing stones areradially disposed around a main body fixedly mounted on a rotatablehoning shaft, each of which hone holders is adapted to be radially,outwardly extruded directly by piston and cylinder means associatedtherewith for polishing an inner surface of a workpiece.

However, such conventional devices of the above described type have suchdisadvantages that when the honing stones have been defaced to apredetermined level, they must be extruded by the defaced amount bymanually loosening the honing stones, which procedure reduces theworking efficiency to a great extent. In other words, in suchconventional devices, in cases where the honing stones have been wornout by a predetermined amount, the hone holders are loosened forinserting spacers below the honing stones with the device stopped so asto extrude the stones outwardly step by step, in which adjustment, themanual insertion of the spacers is very complicated and troublesome,requiring considerable time for the correct setting of the spacers andresulting in low working efficiency.

Furthermore, when applied to honing of the trochoidal form inner surfaceof a workpiece, such conventional devices without proper locking meansfor the honing stones present many disadvantages since radius ofcurvature of the trochoidal inner surface to which the honing stones areapplied continuously varies with large bending moment imparted to thehoning stones due to friction between 'the surfaces of the workpiece tobe polished and the honing stones. Moreover, the large bending momentapplied to the honing stones necessitates the height of the honingstones projecting from the hone holders to be less than a predetermineddegree, while simultaneously the projecting height of the honing stonesfrom the hone holders must be more than a certain degree in order toreduce the number of replacements of the stones due to defacementthereof during polishing.

Such requirements for holding the honing stones securely to the honeholders and for maintaining approximately constant projection of thehoning stones from the hone holders especially in the trochoidal formpolishing can not be met by the conventional honing stone expansiondevices.

Accordingly, an essential object of the present invention is to providean automatic honing stone expansion device which is easy to operate andhigh in working efficiency with substantial elimination of the disadvantages inherent in the conventional devices.

Another important object of the present invention is to provide anautomatic honing stone expansion device which is accurate in functioningwith means for locking amount of honing stones constantly projectingabove hone holders.

According to a preferred embodiment of the present invention, theautomatic honing stone expansion device comprises three hone holdersradially, outwardly disposed at a predetermined angle to one another ona main body which is fixedly mounted on a rotatable hone shaft, each ofwhich hone holders is adapted to be radially, outwardly extruded byexpansion means incorporated in the main body, means for extruding thehoning stones incorporated in each of the hone holders, means forsecurely locking the honing stones provided on the outer part of thehone holders, and automatic pressure cycle control means driven byhydraulic pressure for controlling the hone holder expansion means, thehoning stone extruding means and the honing stone locking means.

In the above described device of the present invention, each of the honeholders is radially, outwardly movable by the expansion means operatedby hydraulic pressure from piston and cylinder mechanisms incorporatedin the main body, while the honing stones are also radially, outwardlyextruded by the extrusion means, through hydraulic pressure,incorporated in the hone holders with the honing stones securely lockedat the extruded position or readily released from the hone holders bysimple wedge action between two tapered plates disposed along the honingstones, which arrangement not only makes it possible to readily extrudethe defaced stones to a necessary extent by the extrusion means veryefficiently, but also is very effective for constantly maintainingproper height of the honing stones especially-in polishing a trochoidalform surface without the complicated procedure of manually insertingspacers for adjusting the height of honing stones as required in theconventional devices.

These and other objects and features of the present invention willbecome apparent from the following description taken in conjunction withthe preferred embodiment thereof with reference to the accompanyingdrawings, in which;

FIG. 1 is a schematic diagram showing a front view, partly in sectiongflf an automatic hone expansion device and hydraulic system associatedtherewith,

FIG. 2 is a top plan view of the device of FIG. 1,

FIG. 3 is a sectional view taken along the line III m of FIG. 1,

FIG. 4 is a sectional view taken along the line IV IV of FIG. 1,

FIG. 5 is a schematic diagram showing a side view of a modification of alocking pin arrangement in FIG. 2,

FIG. 6 is a schematic diagram showing a front view of a modification ofthe device of FIG. 1,

FIG. 7 is a sectional view taken along the line VII VII of FIG, 6,

FIG. 8 is a sectional view taken along the line VIII VIII of FIG. 6, and

FIG. 9 is a sectional view taken along the line IX IX of FIG. 7.

Before the description of the present invention proceeds, it is to benoted that like parts are designated by like numerals throughout theaccompanying drawings.

Referring to FIGS. 1 to 4, the automatic hone expansion device of theinvention generally comprises a hexagonal main body A fixedly mounted onthe rotatable hone shaft s, and three hone holders 2 of approximatelyU-shape, each of which is slidably received in hone expanding means 1disposed on every other side of the hexagonal body A at an angle of toeach other so as to be synchronously moved radially outwardly orinwardly by the action of a pressure Cycle.

It should be noted here that the description of the hone holders 2 ofthe invention is made on one of the three holders 2 for brevity, sincethe other two holders are exactly the same in construction, except forthe hydraulic system which operates the three hone holders 2simultaneously.

In FIG. 1, each of the three hone holders 2 is formed, on the outer partthereof, with a holding portion 3 of a channel shape extending in theaxial direction of the hone shaft s with the inner part thereof formedinto a flange portion 4 which is slidably received in a cylinderHl-wbored in the body A and with a cylindrical portion 5 integrallyformed between the holding portion 3 and the flange portion 4 whichcylindrical portion 5 is also slidably received in a fitting boreconcentrically communicated with the cyclinder H1. In the cylindricalportion 5 of the hone holder 2, there is enclosed an extruding member 6which is also formed with an U- shaped lifting fork 7 on its outer partwith the inner part thereof formed into a flange portion 8 which isslidably received in a cylinder H2 bored in the cylindrical portion 5 ofthe hone holder 2 and with a cylindrical portion 6 of the member 6 alsoslidably received in a corresponding bore concentrically communicatedwith the cylinder H2.

A honing stone clamping member 9 of an approximately channelconfiguration with an U-shape cross section has its one side wallaxially cut in the direction of the hone shaft s to form a thin'and lowwall 9a with the bottom connecting portion 90 of the member 9 formedwith a slit 10 (FIGS. 3 and 4) at the middle portion adjacent to theother side wall 9b of the member 9 to receive the U-shaped lifting fork7 of the extruding member 6. The member 9 isreceived in the holdingportion 3 of the holder 2 and connected to the hone holder 2 by a pin 11inserted through corresponding openings formed in the holding portion 3of the hone holder 2 and the bottom portion 90 of the member 9 in adirection normal to the axis of the hone shaft s. A locking plate 12having many pointed projections or pawls 13 at one side face thereofadjacent to a honing stone l5 and a tapered surface 12a at the otherside face thereof is adapted to press or release the honing stoneagainst or from the side wall 9b of the clamping member 9 by forward orbackward movement of a tapered pressure plate 16 mentioned later, thehoning stone 15 being placed on and in parallel to the outer edge of anextrusion plate 14 which has an elongated cut-out portion 14a (FIG. 3)along the inner edge thereof and another notch 14a in the portionbetween the outer edge thereof and the cut-out portion 14a and which issupported by the U-shaped lifting fork 7 of the extruding member 6.

It should be noted here that the extrusion plate 14 and the honing stone15 described above are slidably mounted in the holding portion 3 of thehone holder 2 so as to be movable toward the surface to be honed of awork piece W in FIG. 1.

The pressure plate 16 is provided with an elongated notch 17 (FIG. 4) inthe middle portion thereof which engages the bottom connecting portion90 of the clamping member 9 with sufficient axial play of the plate 16,and is disposed along one side wall 9a of the channel shaped clampingmember 9 in a position adjacent to and approximately in parallel withthe locking plate 12 with one side face 16a of the plate 16 taperingtoward one end of the plate 16 in the opposite direction to the taper12a on the corresponding surface of the locking plate 12. Accordingly,by pushing forward the pressure plate 16 between the side wall 9a of theclamping member 9 and the locking plate 12, the locking plate 12 ispressed against the honing stone 15 for clamping the same, while bydrawing the plate 16 backward, the honing stone 15 is released. A pairof compression springs 19 (FIGS. 3 and 4) are disposed between thelocking plate 12 and the connecting portion of the honing stone clampingmember 9 for urging the locking plate 12 in the direction of expansionof the honing stone 15. A locking pin 20 (FIG. 2) is threadedly attachedat one end thereof, through an opening 18b formed in the projection 18extending at right angles from one end of the pressure plate 16 towardthe locking plate 12, to a projection 9b extending at right angles fromthe corresponding end of the side wall 9b of the clamping member 9towardthe pressure plate 16, with a compression spring 21 disposedaround the pin 20 between the projection 18 of the plate 16 and a knob20a formed at the other end of the pin 20 so as to constantly urge thepin 20 in the direction shown by a dotted line arrow and consequently tobias the pres sure plate 16 in the direction of a real line arrow.

Referring particularly to FIG. 3, a honing stone locking piston 25 isreciprocatingly disposed in a cylinder H1 formed in the main body A withthe piston rod 26 thereof fixedly connected to a circular disc 27 havingthree arms 28, each radially, outwardly extending therefrom toward thecorresponding projection 18 of the pressure plate 16 so that the outerend of the arm 28- is located adjacent the inner surface of theprojection 18.

Accordingly, when the piston 25 is moved outward, the end of the arm 28engages the projection 18 of the pressure plate 16, drawing the plate 16outward against the force of the spring 21.

It should be noted here that in the hone expansion device of theinvention the clamping members 9, the locking plates 12, the honingstones 15, the pressure plates 16 andthe locking pins 20 are adapted torock about the pins 11 so that the honing stones 15 can follow thesurface of the workpiece W during polishing.

Referring back to FIG. 1, a passage PI for hydraulic fluid leading froma pipe p to a chamber I-Ila above the flange portion 4 of the honeholder 2 in the cylinder H1 formed in the main body A is adapted tocommunicate with a pressure source Ps through switching valves V1 andV2. The cylinder, moreover a branch piping Pla of the pipe P iscommunicated with a regulating cylinder 22 which is also incommunication with another branch piping Plb connected to the two wayswitching valve V2. The regulating cylinder 22 has a piston 24reciprocatingly enclosed therein with its lower limit of strokedetermined by an adjusting bolt 23 threadedly attached to the lowerportion of the cylinder 22 and with the piston 24 urged upward by acompression spring 29 disposed between the lower surface of the piston24 and the lower inner surface of the cylinder 22, and is adapted topass the hydraulic fluid into an upper chamber Ra thereof above thepiston 24 through the switching valves V1 and V2.

A passage P2 for the hydraulic fluid leading from a branch pipe P2a intoa chamber Hlb in the cylinder H] of the main body A below the flangeportion 4 of the hone holder 2 is communicated with the pressure sourcePs and oil tank T through the branch pipe P2a via the switching valve V2for supplying hydraulic pressure to push the hone holder 2 upward sothat each of the three honing stones can be extruded toward the surfaceto be polished of the workpiece W.

Another passage P3 of the hydraulic fluid is provided in the main body Ain a position below and in communication with a central bore 4a formedin a tubular projection 4a extending inward toward the axis of the shafts from the flange portion 4a of the hone holder 2 for supplyinghydraulic pressure into the chamber I-IZb below the flange 8 of theextruding member 6 in the cylinder H2 formed in the hone holder 2, whichpassage P3 is also communicated with the pressure source Ps and the oiltank T through a switching valve (not shown).

By this arrangement, where a new honing stone 15 is mounted in each ofthe three hone holders 2 as shown in FIG. 1, when the switching valvesV1 and V2 are switched over to a respectively with the passage P2communicated with the oil tank T for supplying hydraulic pressure to thepassage Pl, the hone holder 2 moves inward with the hydraulic pressuresimultaneously supplied to the upper and lower chambers Ra and Rb of theregulating cylinder 22, so that the piston 24 is fully raised until itcontacts the upper surface of the upper chamber Ra by the difference ofthe areas of the piston 24 subjected to the hydraulic pressure.

When the switching valves V1 and V2 are switched over to b respectivelyfor supplying the hydraulic pressure to the chamber Hlb of the honeexpansion cylinder H1 through the passage P2, the oil in the chamber Hlaenters the upper chamber Ra of the regulating cylinder 22 through thepassage P1 and the branch pipe Pla, consequently pushing the piston 24downward against the force of the spring 29 until the under surface ofthe piston 21 contacts the tip of the adjusting bolt 23 with each of thethree hone holders 2 expanded to a predetermined extent toward thesurface to be worked of the workpiece W. In other words, the degree ofexpansion of the hone holders 2 is restricted by the length of theportion of the adjusting bolt 23 projecting into the regulating cylinder22.

Referring back to FIG. 3, when the hydraulic pressure is imparted to thechamber 25b of the hone locking cylinder I-Il through a hydraulic system(not shown for moving each of the arms 28 associated with the piston 25in the direction shown by an dotted line arrow, the arm 28 engages theprojection 18 of the pressure plate 16 to push the latter also in thedirection of the dotted line arrow with the plate 16 drawn in the samedirection against the urging force of the spring 21, in which case thepresence of the tapered surfaces 16a and 12a on the plates 16 and 12releases the locking plate 12 pressed against the honing stone 15 andthe extrusion plate 14. In this state, when the hydraulic pressure isintroduced into the chamber H2b of the hone extrusion cylinder H2through the passage P3 via the bore 4a, the extrusion member 6 is movedin the direction shown by a real line arrow to extrude the plate 14 andconsequently the honing stone 15 in the same direction. Meanwhile, sincethe locking plate 12 is released from being pressed against the honingstone l5 and the plate 14, the plate 14 having the longated cutoutportion 14a and the notch 14a passes over the pawls 13 formed on thecorresponding side face of the locking plate 12, thus forcing the honingstone 15 outward to such an extent that the outer edge of the stone 15contacts the surface of the workpiece W to be polished, in which casethe amount of extrusion of the honing stone 15 is predetermined to be anoptimum level in a manner described earlier.

After the honing stone 15 has been extruded as described above, thehydraulic pressure is introduced into the chamber 25a of the honelocking cylinder H] to move each of the arms 28 in the oppositedirection shown by a real line arrow by operating the hydraulic circuitmentioned earlier. Thereupon, the arm 28 moves away from the projection18 of the pressure plate 16 with the pressure plate 16 rapidly moving inthe direction of the real line arrow by the action of the spring 21 soas to move the locking plate 12 toward the side wall 9b of the clampingmember 9 by a wedge ac tion between the surfaces 16a and 12a tapering inthe opposite directions to each other of the pressure plate 16 and thelocking plate 12 and to hold the honing stone 15 securely between theside wall 9b and the locking plate 12 with the honing stone 15 fixed tothe hone holder 2. In this case, if the pointed tips of the pawls 13 ofthe plate 12 and the pointed tips of the notch 14a formed on thecorresponding side of the plate 14 should coincide with one another, thelocking plate 12 supported by the springs 19 moves upward or downward sothat pawls l3 and the notch 14 on the plates 12 and 14 engage with oneanother for positive locking therebetween.

In the above state, the supply of the hydraulic fluid through thepassage P3 is suspended and simultaneously the switching valve V1 isswitched over to a for communicating the passage P1 with the oil tank Tso that the hone holders 2 can be expanded by the hydraulic pressureapplied to the chambers Hlb of the expansion cylinders H1, while thehoning shaft s is rotated by a driving means (not shown) so as to polishthe inner surface of the workpiece W.

On the other hand, when the honing stones 15 have been defaced, optimumamount of extrusion for the honing stones can be continuously obtainedby repeating the extrusion procedure described above.

For replacing the honing stones 15, the workpiece W is removed from themain body A of the honing device with the hydraulic pressure introducedinto the chamber 25b of the honing stone locking cylinder HI forreleasing the locking by the locking plates 12. After new honing stones15 have been mounted in the holders 2, the hydraulic pressure isintroduced into the other chambers 25a of the cylinders Hl fortightening the locking plates 12 and securing; the stones 15 to thehoning stone holders 2.

The tightening of each of the locking plate 12 described as effectedonly by the force of the spring 21 which presses the pressure plate 16inward may be modified to be effected by the pressing force of thespring 21 and the inward pull of the piston 25 in the cylinder III, inwhich case the locking pin 20 is directly connected to the arm 28 asshown in the modification in FIG. 5.

Referring now to FIGS. 6 to 9, there is shown a modification of the honeexpanding device of FIG. 1. In this modification, the pawls 14a formedon one side face of the extrusion plate 14 are adapted to engage thepawls 32 provided on the corresponding side face 31' of a holding member31 received in a channel shaped groove 30 formed in the side wall 9b ofthe clamping member 9. The member 31 is urged toward the pawls 140' onthe plate 14 by a pair of compression springs 33 suitably providedbetween the member 31 and the bottom of the groove 30, and the extrudingplate 14 is also biased to the pawls 32 of the holding member 31 by apair of compression springs 34 provided between the plate 14 and theside wall 9b of the clamping member 9.

Accordingly, in adjusting the extrusion for each of the honing stones 15due to wearing out thereof, when the pressure plate 16 is drawn in thedirection of the dotted line arrow (FIG. 7) by means of the arm 28 as inthe embodiment in FIG. 1, the extrusion plate 14 and the locking plate12 are moved in the direction ofa dotted line arrow (FIG. 9) by therepulsion of the springs 34 with the pawls 14a of the plate 14disengaged from the pawls 32 of the member 31 for loosening the honingstone 15. In this state, when the extrusion member 6 is moved outwardtoward the surface of the workpiece W in the same manner as thatdescribed in the embodiment in FIG. 1, the honing stone 15 together withthe plate 14 is projected radially, outwardly until the stone 15contacts the surface to be worked of the workpiece W, during whichmovement the relative engaging positions between the pawls 14a of theplate 14 and the pawls 32 of the member 31 are changed accordingly.

When each of the honing stones 15 has been extruded to a predeterminedextent, the pressure plate 16 is moved in the direction shown by thereal line arrow in FIG. 7 in the same manner as that described in theembodiment of FIG. 1 so that the pawls 14a of the plate 14 arepositively engaged with the corresponding pawls 32 of the member 31 forpositioning the honing' stone 15 toward the expanding direction thereofand also for pressing the stone 15 against the side wall 9a of theclamping member 9 by the locking plate 12 so as to securely hold thestone 15 between the locking plate 12 and the side wall 9a of theclamping member 9.

Although in the above modification, the description is mainly directedtoward one of the three hone holders 2 for brevity as in the embodimentof FIG. 1, it is needless to say that other two hone holders 2 areexactly the same in construction.

As is clear from the foregoing description, according to the automatichone expanding device of the invention, since the honing stone extrudingmeans is provided in the honing stone holders having expansion means,the defaced honing stones can be readily extruded by a necessary amountso that the honing stones can economically be utilized to the utmostextent along the entire height thereof with the time required forsetting or replacing the honing stones efficiently reduced to a largeextent.

Furthermore, as the extrusion means can normally be locked by lockingmeans, both of which means are operated by hydraulic pressure instead ofextruding the honing stones by manually inserting spacers below thehoning stones as in the conventional devices, not only the workingefficiency is remarkably improved but is is possible to replace thehoning stones automatically since the replacement can be made at thefront of the honing stone holders by merely removing the worn out stonesfrom the stone holders and mounting new stones thereon.

The adoption of the regulating cylinder for adjusting the amount ofextrusion of the honing stones is very advantageous, since the honingstones can be projected from the honing stone holders by an optimumamount by merely adjusting the amount of projection for the adjustingbolt in the regulating cylinder.

Although the present invention has been fully described by way ofexample with reference to the attached drawings, it is to be noted thatvarious changes and modifications are apparent to those skilled in theart. Therefore, unless otherwise such changes and modifications departfrom the scope of the present invention, they should be construed asincluded therein.

What is claimed is:

1. In a honing stone expansion device for use in a honing machine forpolishing a trochoidal form surface of a workpiece which comprises atleast one honing stone holder having a honing stone mounted thereon andradially outwardly disposed around a main body fixedly mounted on arotatable honing shaft, and means for extruding said honing stone holderradially outwardly from said main body, an improvement which compriseshydraulic pressure means communicating with said honing stone holder forexpansion thereof with an inner part of said honing stone holder formedinto a piston reciprocatingly received in a cylinder formed in said mainbody and with an outer part of said holder formed into a channel shapedholding portion, a clamping member of similar shape being received insaid channel shaped holding portion and carried by said holder, a honingstone extrusion member disposed in said honing stone holder with aninner portion of said extrusion member formed into a pistonreciprocatingly received in a cylinder formed in said honing stoneholder for automatically extruding said extrusion member by saidhydraluic pressure means with an outer portion of said extrusion memberadapted to support an extrusion plate on which said honing stone ismounted, regulating means communicating with said hydraulic pressuremeans for extruding said extrusion member a predetermined amount forautomatically adjusting the height of said honing stone, and means forautomatically locking and releasing said extrusion -plate and honingstone to and from said clamping member, said locking means beingoperated by said hydraulic pressure means.

2. In a honing stone expansion device for use in a honing machine forpolishing a trochoidal form surface of a workpiece which comprises atleast one honing stone holder having a honing stone mounted thereon andradially outwardly disposed around a main body fixedly mounted on arotatable honing shaft, and means for extruding said honing stone holderradially outwardly from said main body, an improvement which compriseshydraulic pressure means communicating with said honing stone holder forexpansion thereof with an inner part of said honing stone holder formedinto a piston reciprocatingly received in a cylinder formed in said mainbody and with an outer part of said holder formed into a channel shapedholding portion, a clamping member of similar shape being received insaid channel shaped holding portion, a honing stone extrusion memberdisposed in said honing stone holder with an inner portion of saidextrusion member formed into a piston reciprocatingly received in acylinder formed in said honing stone holder for automatically extrudingsaid extrusion member by said hydraulic pressure means with an outerportion of said extrusion member adapted to support an extrusion plateon which said honing stone is mounted, regulating means communicatedwith said hydraulic pressure means for extruding said extrusion memberby a predetermined amount for automatically adjusting the height of saidhoning stone, and means for automatically locking or releasing saidextrusion plate and honing stone to or from said clamping member, saidlocking means being operated by said hydraulic pressure means andprovided with means for floating said honing stone in said channelshaped holding portion of said holder, said floating means being a pinmovably connecting said clamping member to said channel shaped holdingportion of said holder.

3. A honing stone expansion device as claimed in claim 2, wherein saidlocking or releasing means for said extrusion plate and honing stonecomprises a locking plate having a plurality of pawls on one side facethereof facing said honing stone and said extrusion plate provided witha notch at corresponding side face thereof, and which has a taperedsurface on the other side face thereof, and a pressure plate having aside face thereof facing said tapered surface of said locking plate andtapering in an opposite direction to said tapered side face of saidlocking plate, said locking plate and said pressure plate together withsaid honing stone and extrusion plate being disposed between side wallsof said clamping member so that when said pressure plate is insertedbetween one side wall of said clamping member and said locking plate,said honing stone is pressed against the other side wall of saidclamping member with said notch of said extrusion plate engaged withsaid pawls of said locking plate.

4. A honing stone expansion device as claimed in claim 2, wherein saidlocking or releasing means for said extrusion plate and honing stonecomprises a locking plate having one flat side face thereof facing saidhoning stone and said extrusion plate provided with a plurality of pawlson the side face thereof facing a first side wall of said clampingmember, a holding member having corresponding pawls on a side facethereof facing said extrusion plate and slidably received in a grooveformed in said first side wall of said clamping member, said holdingmember being urged toward said extrusion plate by spring means, saidlocking plate having a tapered surface on the other side face thereof,and a pressure plate with a side face thereof facing said taperedsurface of said locking plate and tapering in an opposite direction tosaid tapered side face of said locking plate, said locking plate andsaid pressure plate together with said honing stone and extrusion platebeing disposed between said first side wall of said clamping member anda second side wall thereof so that when said pressure plate is insertedbetween said second side wall of said clamping member and said lockingplate, said honing stone is pressed against said first side wall of saidclamping member with said pawls of said extrusion plate engaged withsaid pawls of said holding member.

5. In a honing stone expansion device for use in a nously extruding saidhoning stone holders radially outwardly from said main body; an'improvement which comprises hydraulic pressure means communicating withsaid honing stone holders for expansion thereof with an inner part ofsaid honing stone holder formed into a piston reciprocatingly receivedin a cylinder formed in said main body and with an outer part of saidholder formed into a channel shaped holding portion, a clamping memberof similar shape being received in said channel shaped holding portion,a honing stone extrusion member disposed in said honing stone holderwith an inner portion of said extrusion member formed into a pistonreciprocatingly received in a cylinder formed in said honing stoneholder for automatically extruding said extrusion member by saidhydraulic pressure means with an outer portion of said extrusion memberadapted to support an extrusion plate on which said honing stone ismounted, a regulating means communicated with said hydraulic pressuremeans for extruding said extrusion member by a predetermined amount forautomatically adjusting the height of said honing stone, and means forautomatically locking or releasing said extrusion plate and honing stoneto or from said clamping member, said locking means being operated bysaid hydraulic pressure means and provided with means for floating saidhoning stone in said channel shaped holding portion of said holder, saidfloating means being a pin movably connecting said clamping member tosaid channel shaped holding portion of said holder.

6. A honing stone expansion device as claimed in claim 5, wherein saidlocking or releasing means for said extrusion plate and honing stonecomprises a locking plate having a plurality of pawls on one side facethereof facing said honing stone and said extrusion plate provided witha notch at corresponding side face thereof, and which has a taperedsurface on the other side face thereof, and a pressure plate having aside face thereof facing said tapered surface of said locking plate andtapering in an opposite direction to said tapered side face of saidlocking plate, said locking plate and said pressure plate together withsaid honing stone and extrusion plate being disposed between side wallsof said clamping member so that when said pressure plate is insertedbetween one side wall of said clamping member and said locking plate,said honing stone is pressed against the other side wall of saidclamping member with said notch of said extrusion plate engaged withsaid pawls of said locking plate.

7. A honing stone expansion device as claimed in claim 5, wherein saidlocking; or releasing means for said extrusion plate and honing stonecomprises a locking plate having one flat side face thereof facing saidhoning stone and the extrusion plate provided with a plurality of pawlson the side face thereof facing a first side wall of said clampingmember, a holding member having corresponding pawls on a side facethereof facing the extrusion plate and slidably received in a grooveformed in said first side wall of said clamping member, said holdingmember being urged toward said extrusion plate by spring means, saidlocking plate having a ta pered surface on the other side face thereof,and a pressure plate having a side face thereof facing said taperedsurface of said locking plate and tapering in an opposite direction tosaid tapered side face of said locking plate, said locking plate andsaid pressure plate together with said honing stone and extrusion platebeing disposed ing stone is pressed against said first side wall of saidclamping member with said pawls of said extrusion plate engaged withsaid pawls of said holding member.

1. In a honing stone expansion device for use in a honing machine forpolishing a trochoidal form surface of a workpiece which comprises atleast one honing stone holder having a honing stone mounted thereon andradially outwardly disposed around a main body fixedly mounted on arotatable honing shaft, and means for extruding said honing stone holderradially outwardly from said main body, an improvement which compriseshydraulic pressure means communicating with said honing stone holder forexpansion thereof with an inner part of said honing stone holder formedinto a piston reciprocatingly received in a cylinder formed in said mainbody and with an outer part of said holder formed into a channel shapedholding portion, a clamping member of similar shape being received insaid channel shaped holding portion and carried by said holder, a honingstone extrusion member disposed in said honing stone holder with aninner portion of said extrusion member formed into a pistonreciprocatingly received in a cylinder formed in said honing stoneholder for automatically extruding said extrusion member by saidhydraluic pressure means with an outer portion of said extrusion memberadapted to support an extrusion plate on which said honing stone ismounted, regulating means communicating with said hydraulic pressuremeans for extruding said extrusion member a predetermined amount forautomatically adjusting the height of said honing stone, and means forautomatically locking and releasing said extrusion plate and honingstone to and from said clamping member, said locking means beingoperated by said hydraulic pressure means.
 2. In a honing stoneexpansion device for use in a honing machine for polishing a trochoidalform surface of a workpiece which comprises at least onE honing stoneholder having a honing stone mounted thereon and radially outwardlydisposed around a main body fixedly mounted on a rotatable honing shaft,and means for extruding said honing stone holder radially outwardly fromsaid main body, an improvement which comprises hydraulic pressure meanscommunicating with said honing stone holder for expansion thereof withan inner part of said honing stone holder formed into a pistonreciprocatingly received in a cylinder formed in said main body and withan outer part of said holder formed into a channel shaped holdingportion, a clamping member of similar shape being received in saidchannel shaped holding portion, a honing stone extrusion member disposedin said honing stone holder with an inner portion of said extrusionmember formed into a piston reciprocatingly received in a cylinderformed in said honing stone holder for automatically extruding saidextrusion member by said hydraulic pressure means with an outer portionof said extrusion member adapted to support an extrusion plate on whichsaid honing stone is mounted, regulating means communicated with saidhydraulic pressure means for extruding said extrusion member by apredetermined amount for automatically adjusting the height of saidhoning stone, and means for automatically locking or releasing saidextrusion plate and honing stone to or from said clamping member, saidlocking means being operated by said hydraulic pressure means andprovided with means for floating said honing stone in said channelshaped holding portion of said holder, said floating means being a pinmovably connecting said clamping member to said channel shaped holdingportion of said holder.
 3. A honing stone expansion device as claimed inclaim 2, wherein said locking or releasing means for said extrusionplate and honing stone comprises a locking plate having a plurality ofpawls on one side face thereof facing said honing stone and saidextrusion plate provided with a notch at corresponding side facethereof, and which has a tapered surface on the other side face thereof,and a pressure plate having a side face thereof facing said taperedsurface of said locking plate and tapering in an opposite direction tosaid tapered side face of said locking plate, said locking plate andsaid pressure plate together with said honing stone and extrusion platebeing disposed between side walls of said clamping member so that whensaid pressure plate is inserted between one side wall of said clampingmember and said locking plate, said honing stone is pressed against theother side wall of said clamping member with said notch of saidextrusion plate engaged with said pawls of said locking plate.
 4. Ahoning stone expansion device as claimed in claim 2, wherein saidlocking or releasing means for said extrusion plate and honing stonecomprises a locking plate having one flat side face thereof facing saidhoning stone and said extrusion plate provided with a plurality of pawlson the side face thereof facing a first side wall of said clampingmember, a holding member having corresponding pawls on a side facethereof facing said extrusion plate and slidably received in a grooveformed in said first side wall of said clamping member, said holdingmember being urged toward said extrusion plate by spring means, saidlocking plate having a tapered surface on the other side face thereof,and a pressure plate with a side face thereof facing said taperedsurface of said locking plate and tapering in an opposite direction tosaid tapered side face of said locking plate, said locking plate andsaid pressure plate together with said honing stone and extrusion platebeing disposed between said first side wall of said clamping member anda second side wall thereof so that when said pressure plate is insertedbetween said second side wall of said clamping member and said lockingplate, said honing stone is pressed against said first side wall of saidclamping member with said pawls of said extrusion plate eNgaged withsaid pawls of said holding member.
 5. In a honing stone expansion devicefor use in a honing machine for polishing a trochoidal form surface of aworkpiece which comprises a plurality of honing stone holders havinghoning stones mounted thereon and radially outwardly disposed at apredetermined angle to one another on a main body fixedly mounted on arotatable honing shaft, and means for synchronously extruding saidhoning stone holders radially outwardly from said main body, animprovement which comprises hydraulic pressure means communicating withsaid honing stone holders for expansion thereof with an inner part ofsaid honing stone holder formed into a piston reciprocatingly receivedin a cylinder formed in said main body and with an outer part of saidholder formed into a channel shaped holding portion, a clamping memberof similar shape being received in said channel shaped holding portion,a honing stone extrusion member disposed in said honing stone holderwith an inner portion of said extrusion member formed into a pistonreciprocatingly received in a cylinder formed in said honing stoneholder for automatically extruding said extrusion member by saidhydraulic pressure means with an outer portion of said extrusion memberadapted to support an extrusion plate on which said honing stone ismounted, a regulating means communicated with said hydraulic pressuremeans for extruding said extrusion member by a predetermined amount forautomatically adjusting the height of said honing stone, and means forautomatically locking or releasing said extrusion plate and honing stoneto or from said clamping member, said locking means being operated bysaid hydraulic pressure means and provided with means for floating saidhoning stone in said channel shaped holding portion of said holder, saidfloating means being a pin movably connecting said clamping member tosaid channel shaped holding portion of said holder.
 6. A honing stoneexpansion device as claimed in claim 5, wherein said locking orreleasing means for said extrusion plate and honing stone comprises alocking plate having a plurality of pawls on one side face thereoffacing said honing stone and said extrusion plate provided with a notchat corresponding side face thereof, and which has a tapered surface onthe other side face thereof, and a pressure plate having a side facethereof facing said tapered surface of said locking plate and taperingin an opposite direction to said tapered side face of said lockingplate, said locking plate and said pressure plate together with saidhoning stone and extrusion plate being disposed between side walls ofsaid clamping member so that when said pressure plate is inserted betwenone side wall of said clamping member and said locking plate, saidhoning stone is pressed against the other side wall of said clampingmember with said notch of said extrusion plate engaged with said pawlsof said locking plate.
 7. A honing stone expansion device as claimed inclaim 5, wherein said locking or releasing means for said extrusionplate and honing stone comprises a locking plate having one flat sideface thereof facing said honing stone and the extrusion plate providedwith a plurality of pawls on the side face thereof facing a first sidewall of said clamping member, a holding member having correspondingpawls on a side face thereof facing the extrusion plate and slidablyreceived in a groove formed in said first side wall of said clampingmember, said holding member being urged toward said extrusion plate byspring means, said locking plate having a tapered surface on the otherside face thereof, and a pressure plate having a side face thereoffacing said tapered surface of said locking plate and tapering in anopposite direction to said tapered side face of said locking plate, saidlocking plate and said pressure plate together with said honing stoneand extrusion plate being disposed between said first side wall of saidclamping member and a second side wall tHereof so that when saidpressure plate is inserted between said second side wall of saidclamping member and said locking plate, said honing stone is pressedagainst said first side wall of said clamping member with said pawls ofsaid extrusion plate engaged with said pawls of said holding member.